PCI-6221 incorrect analog input readings

[DavidT]

Hello,
Im trying to read analog voltages through a PCi-6221 card using DAQmx. I have two inputs, AI0 is reading a signals from a signal generator (1Hz sine wave) and AI1 is reading a voltage which is output from the AO0 channel of the card. At the tbx-68 terminal I am reading the input voltages with a scope and they are correct, however, when trying to read through LV, im not reading the correct values. eg a sine wave @ 1Hz (0-2V) reads as -2.68 to -2.8 Volts.
Same problem with reading the analog output voltage in the analog input channel. 0V ouput reads throught LV as a 10V, where reading at the terminal gives 0V (or whatever the voltage is).
Not sure what is happening or what I might be doing wrong in my setup so any advice is appreciated.

thanks,
David

Using
LV7.1
Daqmx 7.3

[Mcdan]

DavidT,

I would check to ensure that your input channels' terminal configurations match the way you have your signals wired. If your signals are wired up to an AI channel and an AIGnd pin, then ensure that you are using Referenced Single Ended (RSE) terminal configuration. If you have them wired up to an AI channel and an AI Sense pin, then you should be using Non-referenced Single Ended terminal configuration. If your signals are wired across AI0 and AI8 (for example) then you should be using Differential terminal configuration. By default, the terminal configuration for each channel is assumed to be differential. The easiest way to test this is probably to open up Max, and use the AI test panel. This test panel allows you to easily change the terminal configuration and acquire data. In LabVIEW, this is an input to the DAQmx Create Channel VI.

Hope this helps,
Dan

[DavidT]

Thanks, you are correct. I found the property node to set the channels to RSE and it works perfectly.
Once again, thanks.